Variable displacement piston machine



1963 G. E. BJORKLUND 3,101,060

VARIABLE DISPLACEMENT PISTON MACHINE Filed Jan. 51, 1961 4 Sheets$heet 1 L7G] 2/ 4 P7 l8 I9 23\/ 20 20 ,4 L2 M B 9 2 IN VEN TOR.

Aug. 20, 1963 E. BJORKLUND VARIABLE DISPLACEMENT PISTON MACHINE 4 Sheets-Sheet 2 Filed Jan. 31, 1961 Aug. 20, 1963 G. E. BJORKLUND 3,101,060

VARIABLE DISPLACEMENT PISTON MACHINE Filed Jan. '51, 1961 i 4 Sheets-Sheet a I N VEN TOR.

Guam; [me (Si/aha u/w 20, 1963 G. E. BJGRKLUND 3,101,060

VARIABLE DISPLACEMENT PISTON MACHINE 4 Sheets-Sheet 4 Filed Jan. 51, 1961 INVENTOR.

60: m [If/A Edam 4 u/vp WW MM United States Patent 3,101,060 VARIABLE DISPLACEMENT PISTON MACIHNE Gustaf Erik Bjiirlrlund, Svedenborsgatan 2, Stockholm, Sweden Filed Jan. 31, 1961, Ser. No. 86,051 Claims priority, application Sweden Feb. 4, 1960 9 Claims. ((31. 103-161) This invention relates to a machine for use as a pump, compressor or motor and consisting of a plurality of units, each unit comprising a centrally disposed pintle valve and a cylinder block with pistons reciprocable therein, said pistons engaging a surrounding ring which is mounted eccentrically with respect to the pintle valve and rotatable together with the cylinder block rotating about the pintle valve, and wherein the various units have pressure sides and suction sides having or being adjustable in positions relative to each other in which the forces originating from the pressure difference between the pressure side and suction side of the various units balance each other or can be brought entirely or partly to balance each other.

In piston machines of the type indicated it is desirable to vary the volumetric displacement. To this end, the pintle valve is adjusted relative to the surrounding ring so as to vary the eccentricity. The object of the invention is to provide simple means which render possible such an adjustment in a machine composed of a plurality of units. In accordance with the invention, two or more units of the type indicated are arranged such that their pintle valves are parallel to each other and their eccentric rings directly or indirectly support each other circumferentially, whereby to take up forces originating from the pressure difference between the pressure side and suction side of theunits. The eccentric rings may be operatively connected with each other, preferably by being provided with shafts with gear wheels mounted thereon and meshing with each other. Due to this arrangement motion transmitting engagement of the rings is ensured even if the pressure sides of the various units are directed away from each other, and the rings will be maintained in engagement with each other as a result of the pressures in the various units. F

Due to the parallel arrangement of the pintle valves, simple control members can be used for varying the volumetric displacement. To this end, the pintle valves may be secured to a control device which is common to the various units and adjustable relative to the rings whereby to vary the eccentricity of the rings with respect to th pintle valves. i

If the machine comprises more than two units, the rings may be arranged around a shaft with their peripheries in engagement with said shaft, in which case the rings or hub portions thereof are surrounded by an annular pressure sustaining member common to all of the units. According to a further embodiment of the invention the bearings may be relieved due to the fact that each ring has a circular hub portion on either side of the cylinder block and that the hub portions on one side of the block are internally tangential to a common pressure sustaining member, whereas the hub portions on the other side are tangential to a similar member at places located symmetrically with respect to the places of engagement between the rings and the shaft.

Additional features of the invention will appear from the following description of several embodiments illustrated in the annexed drawing together with a simple machine of the type in question. FIG. 1 is a crosssectional view and FIG. 2 a longitudinal sectional view of the simple machine comprising a single cylinder block to explain the principle of operation of the type of machine which in the form of a unit is comprised in a compound machine according to the invention. FIG. 3 is a cross-sectional view and FIG. 4 an axial section of a machine devised in accordance with the invention and composed of two units. FIG. 5 is a diametrical crosssectional view of a machine composed of four units with the machine casing removed and in accordance with a further embodiment of the invention. FIG. 6 is a partial axial section of such a machine. FIG. 7 illustrates in a manner similar to FIG. 6, but to an enlarged scale, and

more in detail a machine substantially similar to that shown in FIG. 6. FIG. 8 is an axial section of a modification, and FIG. 9 shows a central radial section of a similar modification.

The principle of operation of a machine of the type in question is explained with reference to FIGS. 1 and 2, the machine being assumed to be used as a pump. In FIGS. 1 and 2, reference numeral 1 denotes the frame of the machine, numeral 2 a bearing, numeral 3 a tubular drive shaft mounted in the bearing 2, and numeral 4 an annular driving member which hereinbelow is termed the ring. In FIG. 1, the centre of the drive shaft 3 is indicated at 5, and in FIG. 2 the axis of the drive shaft 3 is indicated by a chain-dotted line 5'. The drive shaft 3 is mounted on a stationary shaft 6 which by means of a locking pin 8 is secured to a bracket 7 on the frame. The shaft 6 extends into the ring 4 and is formed therein with pintle 9 which serves as a pintle valve. The combination of the shaft 6 and the pintle 9 is termed hereinbelow the pintle valve. The pintle 9 of the pintle valve is disposed eccentrically with respect to the inner periphcry of the ring 4. In FIG. 1, the centre of the pintle is indicated at 11, and in FIG. 2 its axis is indicated at 11'. The shaft has two diametrically opposite recesses 12 and 114. The recess 12 communicates through a longitudinal duct 15 in the shaft with an inlet conduit, not shown, for the working medium, and the other recess 14 communicates through a similar duct 16 with an outlet conduit. A cylinder block 17 is mounted on the pintle 9 of the pintle valve and provided with a plurality of preferably cylindrical recesses or bores 18 extending radially toward the centre 11 and receiving each a piston 19, eight bores being provided in the embodiment illustrated. The pistons are movable outwardly and inwardly in thecylinder bores and are in sealing engagement with the walls thereof. The cylinder spaces located inwardly of the pistons can be put into communication with the recesses 12 and 14 in the pintle 9 through individual openings 20.

In order to have the ring 4 and the cylinder block 17 rotate together around the pintle 9 so as to cause the pistons to reciprocate, locking balls or similar members such as described in copending application Ser. No. 820,233, filed June 15, 1959 may be provided between the outer ends of the pistons and the inside of the ring If the ring 4 is the driving member of the machine and isdriven, such as by means of a drive pulley 22 secured to the shaft 3, in the direction indicated by the arrow 23, the machine works as a pump or compressor. The pistons 19 impart rotational movement to the cylinder block 17 due to the locking action at the outer ends of the pistons. Since the cylinder block rotates-on the pintle around the centre 11 and since the ring 4 rotates about the centre 5, the pistons 19' will reciprocate in the cylinders 18 during rotation of the machine, and working medium will be drawn in through the duct and the recess 12 on one side of the central portion 24 of the pintle valve and will enter the cylinder spaces 18 at the inner ends of the pistons 19 located :on that side. After the pistons. have been moved to. the other side of the central part 24- the working medium will be forced out of the cylinder spaces and pass into the recess 14 and theretrom' be delivered through the duct'16. It will be apparent that the pump has a suction side A located on one side of la diametrical plane indicated by a chain-dotted line CC which extends midway between the recesses l2 and 14, and a pressure side B on the other side of said plane.

On the pressure side of the machine there arise pressures between the outer ends of the pistons 19 and the surrounding ring 4; The forces acting at these places are directed radially outwardly [from the centre 11 of the cylinder block 17 and are represented by arrows 11 p and 12 If these forces are resolved into components 'panallel and at right angles to the plane of symmetry C-C it willbe seen that the components v and 11 at two of the pistons balance each other, Whereas the components h and h are added to the tfiorce p acting at right angles to the plane of symmetry. If the pump works against a high pressure the resultant force h +p +h can be very great. In contrast, the [forces acting on the suction side are small and usually negligible. The great dorces on the pressure side result in high pressures on the l caring surfaces between the shatts 3 and 6, which pressures may cause considerable friction losses. Further, small radial relative movements occur between the pintle valve and the ring. A certain noise of rather high pitch is produced as a result of these movements which are synchronous with the pressure variations acting on the pistons as they move from the pressure side to the suction side and vice versa. I

The machineillustrated in FIGS. 3 and 4 may be as l sumed to be used as a motor driven by a liquid under pressure. The machine comprises two units a and b of generally the same construction as that described with reference to FIGS. 1 and 2. The pintle valve 901 or the unit a is parallel to the pintle valve 917 of the unit b. The rings 41:, 4b which surround the cylinder blocks 17a, 17b and cooperate with the pistons 19a, 19b engage each other at their outer peripheries. The rings 4a, 4b are mounted within a surrounding casing by means of pivots 32a, 32b formed on end plates 34a, 34b. The rings are provided at the peripheries of these plates. The bearing clearance around the pivots 32a, 32b is. sufiiciently lange'to permit the rings 4a, 4b to roll directly on each other. 'The pintle valves 9a, 9b are provided with inlet ducts 36a, 36b and inlet ports 38a, 3812 which are By means of the common control member 46 the pintle valves 9a, 9b can be transversely displaced such as to assume more or less eccentric positions with respect to the appertaining rings 4a and 4b, respectively. Thereby, the volumetric displacement of the two units a and b will be varied.

To operate the motor described, pressure medium is admitted through the inlet 5t. Therefrom, the pressure medium enters the cylinders of the two units a, [1 through the duct48, valve ducts 36a, 36b and ports 38a, 3812. Under the action of the pistons 19a, 19b rotational movement is imparted to the cylinder blocks 17a, 17b and the surroundhrg rings 4a, 412. After having performed its 7 work the oil is discharged through the ports 42a, 42b, valve directed toward each other, and with outlet ducts 41hr,

. 40b and outlet ports 42a, 42b which are directed away from each other. The casing 30 of the machine has oblong panallel openings 44 through which the pintle valves 9a, 9b'extend outwards. The outer ends of the valves are attached to a control member 46 in which there is provided a common inlet duct 48 extending between the pintle valves. Liquid, such as oil, under pressure can be {admitted to-the duct 48 through an opening 50'. At its ducts 40a, 40b and outlet ducts 52a, 52b in the control member 46. In the positions shown in FIGS. 3 and 4 the pressure sides of the units a and b are directed towards each other. (The inlet port 38a for the pressure fluid in the unit a is directed towards the inlet port 3812 of the unit 12.) Consequently, during operation the rings 4a, 4b are acted-upon by forces which tend to move the rings into contact with each other. In other words, these forces are taken up by the rings themselves due to their engagement with each other so that the bearings for the pivots 32a, 3219 will be relieved. The output power of the motor can be taken 013? from either of the pivots 32a, 32b.

If the machine shown in FIGS. 3 and 4 is used as a pump and liquid is drawn in through the ducts 36a, 36b, the suction sides of the units a and b will be directed towards each other and the rings 4a, 4b will tend to move away from each other. In this case, gear wheels 54a, 54b may be keyed onto the pivot 32a, 32b and power may be supplied by 'means of a drive shaft 56 which may be integral with either of the pivots 32a, 32b.

The pressure side and the suction side may be brought to change places even without change of the direction of rotation if the control member is adjusted such that the centres of the pintle valves 9a, 9b are displaced from positions on one side of the respective centre of rotation of the rings 4a and 4b (centres of the pivots 32a. and 32b) to positions on the other side of said centres of rotation.

' The embodiment illustrated in FIGS. 5 and 6 comprises four units a, b, c, d which are arranged around a common central shaft 58. The rotor rings Ala-4d of the units have hub portions 60, 60' which are surrounded by annular pressure sustaining members 62 and 62', respectively, which are common to all of the units. These supporting rings 62, 62" may be made of steel and may be dimensioned such as to urge the rings la-4d toward a drum or roll 64 at the end of the shaft 58 so that during operation the shaft 58 will drive the rings ta-4d or will be driven thereby. The pressure sides of the various units a, b, c, d are assumed to be directed toward the roll 64, so that the resultant of the forces originating from the pressure dif-' tferertce between the pressure side and suction side of each unit will be taken up by the central drum 64. In order to maintain the operative engagement of the rings la-4d even if the pressure side and suction side change directions, the supporting rings 62, 62 may be resilient such as to force the rings la-4d against the drum 64. According to a more simple construction, the rotor rings and the drum are provided with intermeshing gear rings 66', 68.

A machine casing 70 common to the units a-d is formed with a central bearing 72 for the shaft 58 and with bearings 73 for the shafts of the pintles 9., Pins 76 may be secured to a detachable end wall 74 of the machine. The pinsycarry rolls 78 which are located between the rotor rings -4a- 4d of the units and engage these rings to prevent tangential displacement of the units. 7

The eccennicity of the rotor rings la-4d with respect to the rotors 80 (cylinder blocks with appertaining pistons) mounted on the pintles 9 determines the capacity of the machine (pump, motor or compressor). The eccentricity can be varied either by tangential displacement of the pintles 9 or by a corresponding tangential displacement of the pins 76 of the rolls 78, as exemplified by the constructions shown in FIGS. 7 and 8.

In the embodiment illustrated in FIG. 7, the casing 70 of the machine has at one end a plate 82 which is guided for turning movement relative to the casing. The plate has a circumferential guide flange 84 and is retained in position by means of a retaining ring 86 which is screwed to the end wall 88. The plate 82 can be turned by means of a control lever 90. Although FIG. 7 shows but one rotor unit, it will be obvious that any suitable number of units may be provided around the central roll or drum 64 formed at the end of the shaft 58. Each rotor unit comprises a cylinder block 17 mounted on a pintle 9 and including pistons 19'. Motion between the cylinder block and the surrounding rotor ring 4 is transmitted by means of locking balls 19". An inlet conduit 92 is provided for the supply of working medium to ducts in the pintle valve and to the cylinder spaces on one side of the rotor, and an outlet conduit 94 is provided for the discharge of the Working medium from the cylinder spaces on the other side of the rotor and from corresponding ducts in the pintle valve (if the machine is to be used as a motor instead of a pump the inlet and outlet change places). The pressure sustaining member consists of a single ring 63. The rings 4 roll on the inner surface of the ring 63. In the same way as shown in FIG. 6, the rings 4 are provided with gear rings 66 which are in engagement with a gear ring 68 on the drum 64. The common shaft 58 is mounted in the casing 7 of the machine by means of a single antifriotion bearing 96 which is substantially relieved as a result of the provision of the pressure sustaining ring 63 and the central drum '64.

To adjust the pintles 9 relative to the surrounding rings 4 so as to vary the volumetric displacement of the machine, (the plate 82 is turned about the axis of the shaft 58 by means of the lever 90. Thereby the eccentricity of the rings 4 with respect to the slide valves can be varied from zero to a positive or negative value. It will be obvious that this machine, .too, can be used either as a pump in which case the shaft 53 is the power input shaft, or as a motor in which case this shaft is the power output shaft.

From FIG. 8 it will be seen that the pins 76 on which the rolls 7% are mounted (see KG. 5) are secured to a turnable control plate 98 which is provided with a lever 199 and is retained on the casing 7b of the machine by means of a central ring 102. If the control plate is turned about the centre of the shaft 58 by means of the lever 1%, the rings 4.a-4d (FIG. 5) are displaced relative to the pintle valves so as to vary the eccentricity and, consequently, the volumetric displacement of the machine. Even in this instance there is provided a pressure sustaining ring 63 for cooperation with the rotor rings of the various units. These rings 4 are each provided with a row of teeth 101 formed between transverse cuts in the central portions of their peripheral surfaces for operative engagement with corresponding teeth 104 on the central drum 64 of the shaft 58. Smooth grooves 106 and 108 corresponding to the teeth are provided in the interior peripheral surface of the annular member 63 and the exterior peripheral surface of the rolls 78, respectively, to avoid intermeshing contact between the teeth and the annular member 63, the rings 4 supporting the annular member 63 and the rolls 78 tangentially only, namely, along lines at both sides of the grooves 166, 108 on the cylindrical surfaces 110, 112.

What I claim is:

1. Machine adapted to operate as a pump, compressor or motor comprising a casing having a plurality of units disposed therein; each unit including a centrally disposed pintle valve having a pressure side and a suction side, a cylinder block surrounding said pintle valve and rotatable with respect thereto, reciprocable piston means mounted in said cylinder block providing working chambers in said cylinder block during rotation thereof, a ring surrounding said cylinder block and being engaged by said piston means, said ring being adapted to rotate about an axis disposed eccentrically with respect to the axis of said pintle valve for reciprocation of the piston means with respect to said cylinder block through the pressure and exhaust positions; means provided in said casing for supporting said pintle valve and ring of each unit, and means to operatively connect said units to drive said ring and cylinder block thereof in rotation through said piston means so that said ring is the driving or driven member, the pintle valves of said units being disposed parallel to each other, the rings of said units being in operative engagement with each other at their high pressure positions to balance the pressure forces of the piston means thereon.

2. Machine according to claim 1 wherein said ring of each unit is provided with a shaft concentric therewith, and gear means mounted on each shaft in intermeshing engagement constituting said means to operatively connect said units.

3. Machine according to claim 1 wherein a central shaft extends into said casing, said units disposed equidistantly around said shaft, the ring of each unit engaging said central shaft.

4. Machine according to claim 1 wherein a central shaft extends into said casing, said units disposed equidistantly around said shaft, the ring of each unit engaging said central shaft, hub means extending from each ring and located centrally with respect thereto, and annular pressure-sustaining means common to all units which surrounds and engages said hub means in tan gential contact therewith to urge the rings of the units towards said central shaft.

5. Machine according to claim 1, wherein a central shaft extends into said casing, said units disposed equidistantly around said shaft, the ring of each unit engaging said central shaft, and annular pressure-sustaining means common to all the units which surrounds and engages the rings thereof to urge them towards said central shaft.

6. Machine according to claim 1, wherein control means are operatively connected to the pintle valves of the units, said control means being adjustable to displace the pintle valves with respect to said rings to vary the eccentricity of the rings with respect to the pintle valves to control the operation of the machine.

7. Machine according to claim 1, wherein a central shaft extends into said casing, said units disposed equidistantly around said shaft, the ring of each unit engaging said central shaft, roll means disposed in said casing, each roll means disposed between two adjacent rings and in externally tangential contact therewitlnpin means rotatably carrying each roll means, and a supporting member adjustably mounted on said casing and carrying said pin and roll means, said supporting member being adjustable to displace the rings relative to the pintle valves to vary the eccentricity therebetween.

8. Machine according to claim 1, wherein a central shaft extends into said casing, said units disposed equidistantly around said shaft, the ring of each unit engaging said central shaft, annular pressure-sustaining means common to all units which surrounds and engages the rings thereof to urge them towards said central shaft, the pintle valves of the units mounted in asupport member on said casing which is adjustable relative to said casing to displace the pintle valves relative to the rings to vary the eccentricity therebetween.

9. Machine according to claim 1, wherein a central shaft extends into said casing, said units disposed equi-' distantly around said shaft, the ring of each unit engaging said central shaft, hub means extending from opposite sides of and concentric with each ring, annular pressure-sustaining means common to all units which surround and engage said hub means in tangential contact therewith to urge the rings of the units towards said central shaft, a supporting member mounted on said casing and being displaceable with respect thereto, roll means mounted on said supporting nieinber, each roll means disposed'between adjacent rings and in externally tangential contact therewith, said supporting member upon being dis- 10 placed relative to said casing causing said pintle valves to be displaced relative to the rings to vary the eccentricity therebetween.

References Cited in the file-of this patent UNITED STATES PATENTS Ellis June 19, 1906 Tompkins Mar. 2, 1909 Worth Sept. 15, 1936 Connor July 11, 1950 Ferris Sept. 5, 1955 FOREIGN PATENTS France Apr. 24, 1952 Germany July 10, 1952 Great'Britain Mar. 4, 1892 Great Britain Apr. 23, 1925 

1. MACHINE ADAPTED TO OPERATE AS A PUMP, COMPRESSOR OR MOTOR COMPRISING A CASING HAVING A PLURALITY OF UNITS DISPOSED THEREIN; EACH UNIT INCLUDING A CENTRALLY DISPOSED PINTLE VALVE HAVING A PRESSURE SIDE AND A SUCTION SIDE, A CYLINDER BLOCK SURROUNDING SAID PINTLE VALVE AND ROTATABLE WITH RESPECT THERETO, RECIPROCABLE PISTON MEANS MOUNTED IN SAID CYLINDER BLOCK PROVIDING WORKING CHAMBERS IN SAID CYLINDER BLOCK DURING ROTATION THEREOF, A RING SURROUNDING SAID CYLINDER BLOCK AND BEING ENGAGED BY SAID PISTON MEANS, SAID RING BEING ADAPTED TO ROTATE ABOUT AN AXIS DISPOSED ECCENTRICALLY WITH RESPECT TO THE AXIS OF SAID PINTLE VALVE FOR RECIPROCATION OF THE PISTON MEANS WITH RESPECT TO SAID CYLINDER BLOCK THROUGH THE PRESSURE AND EXHAUST POSITIONS; MEANS PROVIDED IN SAID CASING FOR SUPPORTING SAID PINTLE VALVE AND RING OF EACH UNIT, AND MEANS TO OPERATIVELY CONNECT SAID UNITS TO DRIVE SAID RING AND CYLINDER BLOCK THEREOF IN ROTATION THROUGH SAID PISTON MEANS SO THAT SAID RING IS THE DRIVING OR DRIVEN MEMBER, THE PINTLE VALVES OF SAID UNITS BEING DISPOSED PARALLEL TO EACH OTHER, THE RINGS OF SAID UNITS BEING IN OPERATIVE ENGAGEMENT WITH EACH OTHER AT THEIR HIGH PRESSURE POSITIONS TO BALANCE THE PRESSURE FORCES OF THE PISTON MEANS THEREON. 